The 11 suspects, believed to have links to terror organization Islamic State, were arrested at the time on charges of planning possible kidnappings, an execution and attacks on Jewish shops as well as other public buildings in Spain.

Ten of the suspects, police said, belonged to the Islamic Brotherhood for Preaching Jihad, a group in Spain suspected of recruiting members for ISIS in Syria, particularly from among converts to Islam.

According to court documents, WSJ reported, the gang was developing plans specifically to bomb a Jewish bookstore, as well as "snatch and behead a captive."

The alleged leader of the group, barber Antonio Saez Martinez, tried to obtain a number of weapons, including a hand grenade, to launch an attack on the store.

Interestingly enough, court documents show, the man Saez tried to obtain arms from was not a fellow Islamist radical, rather an acquaintance named Diego Jose Frias, an activist in a right-wing extremist party.

Explaining the unusual alliance between Islamic extremists and ultra right-wingers was Catalan journalist Jordi Borràs, who told WSJ, “they are united by a common enemy, the Jew.”

Indeed, as Saez wrote in a journal entry, now being processed as court evidence, "I have been absorbed by the global jihad against crusaders and Jews."